When the cooking cavities of hot-air steam ovens are cleaned, the cleaning solution used is sprayed into the dried or moistened cooking cavity. After letting the cleaning solution act for a predetermined period of time, the cooking cavity is rinsed out with water. The lines and nozzles which distribute the cleaning solution are also cleaned.
However, depending on the degree of fouling, these steps are sometimes repeated several times. To prevent leaving scale deposition in the cooking cavity by the rinse water while it is drying off, a dishwashing liquid is introduced into the cooking cavity via the nozzles from which the cleaning solution is sprayed. This results not only in the cleaning of the lines and nozzles, but also, in a decrease of the surface tension of the water, which in turn prevents rapid flowing off of the water and causes the formation of scale residues.
This type of automatic cleaning of the cooking cavity is not only expensive since it must use dishwashing liquid, but is also unsatisfactory with respect to microorganism destruction.